I see. I understood "they" to be "fedora", so I thought you said "fedora forks fedora" i.e. "fork fedora to be the new fedora version". So, I thought you meant "fork RHEL to be the new fedora version". I see that's backwards now.
EDIT: "Fedora is like next major version" also adds to the confusion. If Fedora is like the next major version of RHEL, it makes sense that Fedora forks RHEL and not the other way around.